Process for the manufacture of printing rollers



Patented June 11, 1935 UNITED STATES PROCESS FOR THE MANUFACTURE OFPRINTING ROLLERS Curt Neubert, Giersdorf, near Hirschberg, Germany NDrawing.

Application December 31, 1931,

Serial No. 584,288. In Germany January 8,

2 Claims.

Experiments in using rubber or caoutchouc rollers instead of gelatinerollers in rotary printing and like arts have frequently been made inthe past. They have, however, not led to the desired result, as it wasnot possible to produce rubber and caoutchouc rollers of qualitiessomewhat similar to those of gelatine rollers, because the rubber orcaoutchouc rollers all, to a greater or less extent, have the samedisadvantage of swelling and changing their surface as soon as they getinto contact with organic solving means, and further of inducing thecolour to dry up too quickly and of lacking the quality of adhesioncharacteristic of gelatine rollers. On the other hand gelatine rollerseasily become brittle and unelastic through the colours or dye-stuffpenetrating into them and are apt to get soft when an increasedtemperature is used, so that they lose their shape andmust be recastmany a time.

An intimate connection between the caoutchouc and the gelatine mass wasnot possible up to now, because solutions of caoutchouc could only beobtained by means of benzine, naphtha, benzol or the like, which latter,however, were repelled by the gelatine mass containing water.

The purpose of the present invention now is to avoid these disadvantagesand obtain a combination of the advantages named as well as an intimatemixture of both original products, and especially to produce a greaterdurability of the rollers in connection with the colours added and anincreased resistance with regards to the organic solving means.

For this purpose according to the invention a fluid caoutchouc-milk isintimately mixed with glycerine as well as with colloidal bodies, suchas molten gelatine, and heated together therewith until a uniform,homogeneous mass is obtained, which can easily be cast into moulds orotherwise worked up to obtain any desired shapes.

In special there are used for this purpose preferably so-calledcaoutchouc-milk concentrations, such as revertex, only known since ashort time. These concentrations can easily be in their aqueous stateintimately mixed with glycerine as well as with colloidal bodies, suchas molten gelatine, whereby a product is obtained which can easily becast and shaped and. is consequently particularly adapted to be used forrollers, because of containing the qualities and advantages of bothcaoutchouc as well as gelatine-mass used up to now.

At the same time it is possible to change the quantities of thecaoutchouc-concentrations in relation to the quantities of the othercomponents, such as glycerine, gelatine, at will and adapt them to anypurpose for which the rollers are to be used.

If the fluid mass thus obtained is for instance cast into the shape of aroller and on its cooling down the cover is removed, it only remains todip the same, for the purpose of coagulating the caoutchouc-particles,into acetic acid or into other known means for hardening the caoutchoucand to then vulcanize the same in any known manner.

By way of example the following ingredients are given for the quantitiesto be used:

20 kilos caoutchouc-concentration and 20 kilos gelatine are meltedtogether with 40 kilos glycerine and stirred until a uniform andhomogeneous mass is obtained. This mass can also be coloured by addingdye-stuff thereto and made heavier by means of chemicals or the like.

What I claim is:

l. The process of making printing rollers including the steps of mixingsubstantially one part concentrated aqueous caoutchouc dispersion onepart gelatinous substance and two parts glycerine, coagulating themixture, and vulcanizing the coagulate.

2. The process of making printing rollers including the steps ofintimately mixing substantially one part heated concentrated aqueouscaoutchouc dispersion, one part molten gelatinous substance. and twoparts heated glycerine, molding the resulting homogeneous mass to thedesired shape, cooling the roller to a solidified state, treating theroller with an aqueous-caoutchouc-dispersion coagulant, and vulcanizingthe roller.

CURT NEUBERT.

